Abstract
Summary
Implantation of rats with growth hormone- and prolactin-secreting pituitary tumors cause weight reduction of the host's pituitary gland. This change was accompanied by a decrease in the pituitary content of TSH and a fall in 131I uptake by the thyroid gland in rats with prolactin- and growth hormone-secreting pituitary tumor MtTW5. These results correlated well with the finding that the proportion of organified iodine and the intrathyroid to serum iodine ratio, in the presence of high concentrations of stable iodine, were higher in the tumor bearing rats. The amount of circulating free thyroxine was measured and found to be slightly lower in tumor-bearing rats. It is suggested that the pituitary tumor hormones have a direct suppressive effect on the host's pituitary gland production of TSH and thus indirectly decrease thyroid function.
Get full access to this article
View all access options for this article.